This application is related to International Application Ser. No. PCT/US97/04859 entitled PNEUMATIC TIRES WITH VULCANIZED INNERLINER AND METHOD FOR UTILIZING INNERLINER, filed Mar. 25, 1997 having a common assignor with the present application and is further related to International Application Ser. No. PCT/US97/23,005 entitled METHOD AND APPARATUS FOR BUILDING PNEUMATIC TIRES IN AN IMPROVED TIRE MOLD.
The present invention relates to an improved method of storing tire innerliners. More particularly, the present invention relates to a vulcanized innerliner and the utilization of the vulcanized innerliner in the manufacture of original and retreaded tires. More specifically, to a unique method of storing such innerliners.
The tire industry has tried to eliminate the need for curing bladders used in the production of original tires for years. For example, U.S. Pat. No. 3,143,449 discloses a splice-free unvulcanized barrel-shaped innerliner for completely sealing the inside of a green tire against the escape of pressurized fluid into the tire body during the vulcanization operation in an entire vulcanizing mold. In U.S. Pat. No. 4,166,883 (""883) a method of retreading tires with room temperature gas or water instead of a typical use of an inflatable curing bladder is disclosed. The ""883 patent also disclosed a partially cured or completely cured innerliner that has its ends joined by a bevel spliced or secured with a locking strip of uncured or partially cured stock across the two ends end-butted together as is conventionally done in new tire construction. The inclusion of a partially cured, or completely cured innerliner also allowed for the molding and forming of a green tire by injecting steam or hot water directly against the inner toroidally-shaped surface of the green tire, i.e. the surface formed by the innerliner, to expand the green tire into the mold walls to mold the tire and then cure vulcanize the tire. The two related ways of preparing a spliceless prevulcanize or partially vulcanize innerliner were disclosed in the related applications above. In those applications, a spliceless but partially cured or totally cured innerliner was constructed. The innerliner had a somewhat cylindrical shape in its manufacture in one preferred embodiment. The cylindrical shaped innerliner had a contoured interior surface that upon insertion into a tire would upon expansion stretch to a rather uniform thickness.
It is apparent that there was a need to provide an improved method of storing such components so that they are not damaged during normal storage and that they are maintained in a relatively compact, yet clean environment.
It is an object of the present invention to provide an elastomeric innerliner (10) for pneumatic tires (1) that can be compactly stored up until the time of use. It is also an object of the present invention to provide an at least partially cured elastomeric innerliner (10) which has the surfaces that will contact the tire (1) upon assemble maintained in a very clean environment.
It is a further object of the invention to maintain the innerliner (10) in its as-stored condition as soon as possible from the time it is manufactured. It is an additional object of the present invention to minimize the amount of outgasing or exposure to oxidization that can occur as a result of storage.
In accordance with the preferred embodiment of the invention, the innerliner (10) is constructed in a cylindrical shape. The splice-free, vulcanized or partially vulcanized innerliner (10) of the present invention is first mounted onto a tire building drum (5) followed by the remainder of tire components needed to form a completed, uncured tire assembly (1). Prior to being sent to a tire building drum (5), the innerliner (10) after being manufactured in a spliceless cylindrical shape is preferably converted into a solid toroidal shape (10A) for storage as disclosed below.
The method of preparing an innerliner (10) for storage and subsequent use in the manufacture of a tire (1), the innerliner (10) having a cylindrical shape having a first end (2) and a second end (4) and a radially inner surface (44) and a radially outer surface, comprises the steps of rotating the first end (2) upon itself and continuing the rotation spirally traversing to the second end (4), thereby forming a solid toroidal shape having a portion of the radially inner surface (44) exposed.
When ready for manufacturing the tire (1), the toroidally-shaped innerliner (10A) is placed over a cylindrical building drum, and by clamping the second end (4) while unrolling the innerliner (10) to the first end (2), the innerliner (10) is returned to a cylindrical shape with the radially inner surface (44) inward of the radially outer surface (42).
In an alternative embodiment when using a green spliceless innerliner or uncured innerliner or a partially cured innerliner (10), it may be preferable to add a separation liner (6) to the innerliner""s radially outer surface (42) prior to rotating the first end (2). The method of manufacturing the innerliner (10) may further include the step of curing or partially curing the innerliner prior to forming the toroidal shape (10A).